Starter gearing for internal combustion engines



Apxjll 21, 1959 J. J. sABATlNl 2,882,733

STARTER GEARINGYFOR INTERNALCOMBUSTION ENGINES Filed Dec. 15,y 1955 2v Shams-Sheet 1 IN V EN TOR.

April 21 1959 J. J. sABATlNl y2,882,733

STARTER GEARING FOR INTERNAL COMBUSTION ENGINES Filed Dec. 15, 1955 2 Sheets-SheetI 2 65 66 Q w j' 6 iisgmylgwli 3 7J/MJS WITNESS:

A TORNEY nted States Patent STARTER GEARIN G FOR INTERNAL COMBUSTION ENGINFS John J. Saba Elmira, N Y., assignor to Bendix Aviation Corporation, Elmira Heights, N.Y., a corporation of Delaware Applicah'on December 15, 1955, Serial No. 553,324

Claims. (Cl. 74-6) nected to rotate with the power shaft by means of an overload slip coupling and an overrunning clutch.

The present invention is in the nature of an improvement over the structure shown in the application of Miller Ser. No. 511,828 iled May 31, 1955, now Patent #2,782,643.

In starter gearing in the type disclosed in the applica- I' tion of Miller above cited, a drive pinion is shifted into and out of engagement with an engine gear and rotated by a motor shaft to crank the engine. For this purpose the pinion is connected through a dental type of overload s'lip coupling to a sleeve which is splined on the motor shaft. In order to facilitate the meshing operation, and to insure that the cranking load is not applied until the pinion is fully meshed wtih the engine gear the connection from the power shaft to said sleeve is by means of spiral splines so inclined so as to traverse the pinion toward its fully meshed position responsive to rotation of the motor shaft, said meshed position being defined by a stop ring on the motor shaft.

In such installations as heretofore constructed, the end thrust of this spiral spline connection is imposed on the dental overload slip coupling in such manner as to ailect the operation of said coupling and cause its load carrying capacity to vary from its original calibration.

It is an object of the present invention to provide a novel starter gear of the above type in which the calibration of the slip coupling is not affected by end thrusts applied to the assembly.

It is another object to provide such a device incorporating means independent of the overload slip coupling members for transmitting axial thrust to the pinion.

Further objects and advantages will be apparent from thefollowing description taken in connection with the accompanying drawings in which:

Fig. l is a side elevation, partly broken away and in section, of a preferred embodiment of the invention showing the parts in normal or idle position;

Fig. 2 is a. similar view showing the parts in cranking position;

Fig. 3 is a similar view showing the parts in the positions assumed after the engine starts and causes the pinion to overrun the motor shaft;

Fig. 4 is a detail in perspective of the shifting sleeve with its means for transmitting thrust directly to the pinion;

Fig. 5 is a detail in perspective of the thimble surrounding the coupling and clutch and forming part of the controlling means therefor;

Fig. 6 is a view similar to Fig. 1 of a second embodiment of the invention;

Fig. 7 is a view similar to Fig. 6 showing the parts in cranking position; and

Fig. 8 is a View similar to Fig. 6 showing the parts in the positions assumed when a tooth of the pinion abuts against a tooth of the engine gear during the meshing operation.

In Fig. l of the drawing there is illustrated a power shaft 1 having a portion thereof formed with sprally extending splines 2 on which a sleeve 3 having corresponding spline grooves is slidably mounted. A pinion 4 is slidably and rotatably mounted on a reduced extension 5 of the power shaft for movement into and out of mesh with a gear 6 of the engine to be started, the meshed position of the pinion being deilned by a stop ring 7 iixed on said shaft. The sleeve 3 is formed with a radially extending flange 8, and means for shifting the sleeve axially is provided comprising a shifting fork 9 having rollers 11 engaging in a collar 12 mounted on the sleeve pressed against a lock ring 13 thereon by means of a meshenforcing spring 14 located between the shift collar 12 and the flange 8 of the sleeve.

As best shown in Fig. 4, the sleeve 3 is provided with a forked extension of enlarged diameter, the tines 15 of which extend axially into engagement with a llange or ring member 16 rigidly mounted in any suitable manner on the pinion 4 whereby meshing movement of the sleeve by the shifting fork 9 is transmitted directly to the pinion to move it into engagement with the engine gear as shown in Fig. 2.

Means for rotating the pinion 4 from the sleeve is provided comprising a driving dental coupling member 17 which is slidably received in the forked end 15 of the sleevev 3 and is provided with radial projections 18 extending between the tines 15 to form a splined connection with the' sleeve. Coupling member 17 is provided with teeth 19 having inclined driving surfaces arranged to cooperate with similar teeth 21 on a driven coupling member 22 which is slidably journalled on the reduced portion 5 of the power shaft and is formed with overrunning clutch teeth 23 cooperating with similar teeth 24 on the ring member 16 fixed to the pinion 4 which ring member thus constitutes a driven overrunning clutch member.

Means for yieldably resisting the wedging apart of the coupling members 17, 22 is provided comprising a thimble 25 surrounding the coupling and clutch members, retained y on the forked end 15 of the sleeve 3 by a lock ring 26,

' and having an external shoulder 27 forming an abutment for a compression spring 28 consisting of a plurality of spring washers. The opposite end of the spring 28 bears against a thrust ring 29 seated in the end of a barrel 31 which surrounds the spring and has an inwardly extending flange 32 which bears against the ring member 16 on pinion 4.

The shoulder 27 on the end of thimble 25 is normally seated against the flange 32 of barrel 31 to maintain the spring 28 under initial compression. A light compression spring 33 located within and between the coupling members 17, 22 serves by its expansion to normally hold the clutch teeth 23, 24 of the overrunning clutch members in engagement.

In operation, starting with the parts in the positions illustrated in Fig. l, movement of the shifting fork 9 to the right either manually or by an electromagnet causes the sleeve 3 to be similarly shifted by means of the spring 14, which shifting movement is transmitted by the tines 15 on the sleeve to the ring 16 and pinion 4 to move the pinion into mesh with the engine gear 6 and against the stop ring 7. The starting motor is then energized in the customary manner, whereupon rotation of the motor shaft 1 in the direction of the arrow is transmitted through splined connection 2 to the sleeve 3 and from the sleeve through projections 18 to the driving coupling member 17. The latter is thereby caused to rotate the driven coupling member 22, at the same time pressing it axially into firm contact with the driven overrunning clutch teeth 24 to form the driving connection to the 4pinion 4.

Wedging apart of the coupling members 17, 22 `is resisted by the compression spring Y28 asshown in Fig. 2, but vif overloads are encountered, as at 'the time of initial energiz'ation of the starting motor, the teeth 19, 21 of the coupling members are permitted to slip over each other until the overload is dissipated. l

` It will be noted that the thrust of the coupling members 17, 22 is contained by 'the thimble 25, 'spring '28 `and barrel 31, while the thrust generated on the sleeve 3 by the reaction of the spiral splines 21 is transmitted directly through tines 15 to the pinion 4 and merely serves to press the pinion against the stop ring 7 without aifecting the calibration of Vthe overload slip coupling.

In Figs. 6, 7 and 8 of the drawing the transmission of thrust from the spirally splined sleeve to the pinion is accomplished similarly by means of somewhat different structure.

In Fig. 6 of the drawing the power shaft 61 has a sleeve `63 mounted thereon lby means of spiral splines 62. A shift collar 64 receiving the end of a shift fork 65 is urged against a lock ring 66 on the sleeve 63 by means of a mesh-enforcing spring 67 located between the collar 64 and a compression spring 70 formed of a plurality of spring washers seated against a ange 68 Iou the end of the sleeve.

The flange 68 is formed with teeth A69 having inclined driving surfaces so as to constitute a driving overload slip coupling member which cooperates with a similarly toothed driven coupling member 71. Coupling member 71 is also provided with overrunning clutch teeth 72 engaging similar clutch teeth 73 on a driven overrunning clutch member 74 splined on the hub of a pinion 75 and retained thereon by a lock ring 76. Pinion 75 is `and the calibration of this spring is not affected by the end thrust of the spline connection 62, 63 since that thrust is transmitted through the spacing ring 77 directly to the pinion.

Although but two embodiments of the invention have been shown and described in detail it will be understood that other embodiments are possible, and changes may be made in fthe design and arrangement of the parts without departing `from 'the spirit of the invention.

I claim:

l. ln starter gearing for internal combustion engines; a motor shaft, a sleeve spirally splined thereon, a pinion slidably journalled on the motor shaft, means for transmitting torque from the .sleeve to the pinion including a dental type overload slip coupling having teeth with wedging driving surfaces, a dental Itype overrunning clutch and means for yieldingly resisting slippage of the coupling; means for shifting the sleeve axially on the motor shaft, thrust means for transmitting such axial movement directly and positively to the pinion, `inclepeudently of said coupling, to move the pinion into mesh with a gear of the engine to be started; and ymeans on the motor shaft defining the meshed position of the pinion; the .means for transmitting axial movement 4of coupling'and clutch for resisting axial separation `of the sleeve and pinion irrespective of axial thrust of said sleeve.

2. `yStarter gearing as set forth in claim kl in which .l the `thrust member between the sleeve and pinion is in slidably journalled on a smooth reduced portion 78 of the motor shaft 61 for movement into and out of mesh with an engine gear 79, its meshing position being defined by a stop ring 81. A spacing ring 77 is mounted loosely on shaft 61 between the sleeve 63 andthe hub of the pinion 75 andserves to transmit the end thrust of the sleeve 63 directly to the pinion 75 .in order to move it into mesh with the engine gear.

A barrel member 82 surrounds the coupling and clutch members as well as the compression spring 70 and is provided with an internal ange 83 cooperating with driven overrunning clutch member 74. Barrel member 82 also has an internal shoulder 84 spaced from the ange 83 against which the driving `coupling member 68 is pressed by the spring 70, which is retained in the barrel by a lock ring 85. A light clutch spring 86 located between the coupling members 68, 71 maintains the overrunning clutch teeth 72, 73 normally engaged.

In the operation of this embodiment of the invention the meshing movement of the sleeve 63 `by the shifting fork 65 is ytransmitted through the spacing ring 77 to the pinion 75 to meshv the pinion with the engine gear. Rotation of the power shaft is transmitted through `the coupling members 68, 71 and overrunning clutch teeth 72, 73 to the pinion to rotate the engine gear. The tendency of the coupling members to wedge apart .is resisted by the spring 70 as lcontained by the barrel v82,

the form of a forked extension of the sleeve, the driving member of the overload slip coupling having spline projections slidably received between the tines of said forked extension.

3.1Starter gearing as set forth in claim 2 includingl the other end; said means for yieldingly resisting slippage initial compression.

4. Starter gearing as set forth in claim 1 in which said thrust member is in the form of a spacing .ring

between said sleeve and pinion slidably journalled onthej' power shaft.

5. Starter gearing as set forth in claim 4 in which the driven member ofthe overrunning clutch is `nonrotatably mounted on the pinion, and in which the means `for yieldingly resisting slippage of the overload coupling comprises a compression spring, said vbarrel y member cooperating with the spring to limit separation of said members.

References Cited in the le of this patent UNITED STATES 'PATENTS Miller May l5, 1956 

